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authorNicolas Pitre <nicolas.pitre@linaro.org>2012-11-26 22:48:55 -0500
committerNicolas Pitre <nicolas.pitre@linaro.org>2013-08-05 00:12:41 -0400
commit272614351423ce8c37ff730efc130e5b73fe64f5 (patch)
tree58f30d7dc15915ea1022e65256732a5115117f88 /arch/arm/common
parent38c35d4f2e408c369e3030f0717d35ad443d9223 (diff)
downloadop-kernel-dev-272614351423ce8c37ff730efc130e5b73fe64f5.zip
op-kernel-dev-272614351423ce8c37ff730efc130e5b73fe64f5.tar.gz
ARM: bL_switcher: filter CPU hotplug requests when the switcher is active
Trying to support both the switcher and CPU hotplug at the same time is tricky due to ambiguous semantics. So let's at least prevent users from messing around with those logical CPUs the switcher has removed and those which were not active when the switcher was activated. Signed-off-by: Nicolas Pitre <nico@linaro.org>
Diffstat (limited to 'arch/arm/common')
-rw-r--r--arch/arm/common/bL_switcher.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index 0e4fb3e..335ff76 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -554,6 +554,26 @@ static int __init bL_switcher_sysfs_init(void)
#endif /* CONFIG_SYSFS */
+/*
+ * Veto any CPU hotplug operation on those CPUs we've removed
+ * while the switcher is active.
+ * We're just not ready to deal with that given the trickery involved.
+ */
+static int bL_switcher_hotplug_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ if (bL_switcher_active) {
+ int pairing = bL_switcher_cpu_pairing[(unsigned long)hcpu];
+ switch (action & 0xf) {
+ case CPU_UP_PREPARE:
+ case CPU_DOWN_PREPARE:
+ if (pairing == -1)
+ return NOTIFY_BAD;
+ }
+ }
+ return NOTIFY_DONE;
+}
+
static bool no_bL_switcher;
core_param(no_bL_switcher, no_bL_switcher, bool, 0644);
@@ -566,6 +586,8 @@ static int __init bL_switcher_init(void)
return -EINVAL;
}
+ cpu_notifier(bL_switcher_hotplug_callback, 0);
+
if (!no_bL_switcher) {
ret = bL_switcher_enable();
if (ret)
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